A Facile Method for Regioselective 6,7-Disubstitution of Pteridine.-Among several known organocopper reagents, only copper acetylides coordinated by lithium iodide (II) react with triflate (I) to give the corresponding 7-alkynyl derivatives (III) regioselectively. Products (IIIc) and (IIId) are similarly reactive as triflate (I) in nucleophilic substitution reaction with MeONa. -(MURATA, SHIZUAKI; SEO, CHIHIRO; KUJIME, MASATO;